The FDA does not currently regulate E-cigarettes, however growing research from around the world has identified risks to smokers and those nearby, inhaling secondhand "vapor".
Many state agencies are already beginning to view E-cigarettes the same as conventional forms of smoking (cigarettes, cigars, pipes) in their laws.
A more comprehensive study is needed by the FDA, and if it is found that they pose a health risk (to direct users, or second hand), E-cigarettes companies should be required to label and advertise their products as such.